I try to turn a pc-fan on an off (maybe pwm later).
For this I try to use mosfets but could not get them to run .
First try was a P0903bdl
First problem was that it didn't open when I power the gate pin from nodemcu (3.3v).
I assume that is because of the gate threshold of 3v and the difference of 0.3v is to little?
Because of this assumption I applied 12v to the gate pin. That seemed to work, fan started spinning but soon I noticed that I can't stop it even with gate pin to ground.
All wires detached I can measure continuity between source and drain... So I think it's toast?! But why?
Next victim/try was a sm2558n
I hoped that it will work because of the lesser gate threshold (2.5v) but this thing acts strange.
With nothing attached there is no continuity between source and drain. But when I apply 12v to the source it gets conductive no matter what I do with the gate ( ground/not connected).
Is this normal behavior or is that one broken to?
I never worked With mosfets before and I think I miss something important when locking at the datasheets